Internal combustion engine for oil testing

ABSTRACT

An internal combustion engine for oil testing, comprising two separate lubricating circles, the first of which is supplied with the oil to be tested, and the second with ordinary lubricating oil, each of the lubricating circles being associated with a separate oil chamber in the crankshaft housing, said oil chambers being separated from each other by means of a partition of the crankshaft housing providing an oil-tight seal.

Q Umted States Patent 11 1 Scheiterlein 1 Aug. 29, 1972 [54] INTERNAL CONIBUSTION ENGINE FOREIGN PATENTS OR APPLICATIONS FOR TESTING 667,001 11/1938 Germany 123/196 R [72] Inventor: Andreas Scheiterlein, Graz, Austria Primary Examiner-Manuel A. Antonakas [73] Asslgnee' Hans Llst Graz Austria Attorney-Watson, Cole, Grindle & Watson [22] Filed: Jan. 22, 1971 21 Appl. No.: 108,928 [57] ABSTRACT An internal combustion engine for oil testing, com- Foreign Application Priority Data prising two separate lubricating circles, the first of which is supplied with the oil to be tested, and the Jan. 7, 1971 Austna .A 94/71 ond with ordinary lubricating oil, each of the 52 US. (:1. ..1 lubricating circles being mime! with a Separate i511 1m. 01 170 chamber in crankshaft Said chambers 58 m f being separated from each other by means of a parti- 1 0 Search 123/196 184/6 6 6 13 tion of the crankshaft housing providing an oil-tight [56] References Cited Seal- UNITED STATES PATENTS 3 cm 5 F} T 1,370,927 3/1921 Staude 123/196 R X 2,743,627 5/1956 Christensen ..184/6.l3 X

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Mill illil INTERNAL COMBUSTION ENGINE FOR OIL TESTING The invention relates to an internal combustion engine for oil testing comprising a lubricating circle impinged upon by the test oil.

Oil-testing engines of this type are used for the development and testing of lubricating oils and are generally single-cylinder engines comprising serially produced gearing elements, cylinder heads, cylinder liners and combustion systems.

With conventional types of oil-testing engines the oil to be developed or tested is delivered to the ordinary lubricant-circulating system of the engine and main and connecting-rod bearings, toothed wheels, valve gear wheels, camshafts and fuel-injection pumps are lubricated by means of the test oil. The use of oil-testing engines of conventional design is, however, disadvantageous insofar as relatively large quantities of test oil are required to properly supply all bearings of the engine with lubricant.

Another disadvantage of known oil-testing engines resides in the fact that owing to the considerable size of the lubricated surfaces, draining of the test oil takes a comparatively long period of time, thus delaying completion of the testing process. Furthermore, with oil-testing engines of the known type, the test oils and lubricants still in their research stage have to be produced in laboratories involving relatively high cos and loss of much valuable time.

It is therefore, the object of the present invention to provide an internal combustion engine for oil testing, wherein the amount of oil to be tested is substantially reduced and the time required for testing considerably shortened. For that purpose, according to the invention in addition to the lubricating circle impinged upon by the test oil, an additional lubricating circle fed with ordinary lubricating oil is provided, and the entire lubricated interior of the engine divided into separate oil chambers sealed off one against the other, each of the said chambers being associated with one of the two lubricating circles. This arrangement makes it possible to restrict the oil test to special areas of the internal combustion engine, mainly to such motor elements as are subject to particular stress, thereby reducing the consumption of expensive test oil to the minimum. As the quantity of test oil required is lessened, so are of course, also time and expense involved in the process. Since the two lubricating circles of the engine are independent from each other, lubrication of low-stress engine parts with. cheap commercial lubricating oil cannot have any detrimental effect upon the result of the test.

For the first time, the present invention offers a possibility of studying the behavior of test oils as applied to different areas of the engine and of obtaining valuable knowledge of their particular usefulness.

According to a preferred embodiment of the invention, such components of the engine as require particularly effective lubrication in view of the high thermal and mechanical stresses to which they are subject in operation, such as connecting-rod bearings, pistons and valves, are connected to the lubricating circle impinged upon by the test oil. The oil chamber associated with this lubricating circle is separated from the other oil chamber supplied with ordinary lubricant by means of a preferably inclined partition of the crankcase located below the crankshaft on the one hand, and by means of a sealing ring in such places where parts of the driving gear extend from one oil chamber into the other. While the relatively small quantities of test oil are drained into an oil sump preferably arranged on a side of the crankcase below the said partition, the lubricant pertaining to the second lubricating circle is collected as is customary with internal combustion engines of standard design, in the lower portion of the crankcase serving as an oil pan, without ever coming into contact with the test oil. Preferably the bearings of the fuel-injection pump and of the counterbalance shaft, if any, are connected to the lubricating circle impinged upon by lubricants of a commercial variety in addition to the main bearings, toothed wheels and the camshaft. All of these lubrication points communicate via their respective connecting ducts with the oil sump of the crankcase located below the partition.

For the purpose of performing oil tests involving increased aeration or oxidation of the test oil, according to another feature of the invention the partition of the crankcase is provided with an aperture which can be closed by means of a removable cover and through which the two oil chambers can communicate with each other. For the purpose of removing the cover a lockable lateral opening can be provided on the crankcase through which the screws and bolts of the generally divided connecting-rod bearing are accessible. Thus a high degree of versatility of the oil-testing engine is achieved without complicated transformations of the engine.

According to a further feature of the invention, the crankshaft bearings are included in the lubricating circle fed with commercial lubricants, a sealing ring being provided between each crankshaft bearing and the adjacent crank web. Since crankshaft bearings which are subject to considerable mechanical stress require a comparatively large amount of lubricant, the design according to the invention is conducive to a further reduction of test oil consumption.

According to the invention it is, however, also possible to include the crankshaft bearings upon by the test oil and to provide a sealing ring in front of every crankshaft bearing. In the event of special tests this arrangement can be of considerable importance for the valuation of the test oil.

An oil testing engine according to the invention is also suitable for the performance of oil tests for the purpose of examining the behavior of the test oil under a predominantly thermal stress. According to the invention, in this special case a spacer tightly separating the crank space from the cylinder chamber is inserted between the crankcase and the cylinder block, only the lubrication points located above the spacer being connected to the lubricating circle impinged upon by the test oil. Thus the test oil is primarily exposed to the high temperatures of the pistons and of the working surfaces of the cylinder produced as a result of the combustion process, so thatthe test will provide a clear picture of the influence of high temperatures on the quality of the test oil.

According to another embodiment of the invention, internal combustion engines for oil testing of the lastmentioned design comprise a spacer serving as a guiding means for a crosshead shoe to which the connecting rod is hinged on the one hand, and a push rod flexibly mounted on the piston on the other hand, the said push rod extending through a cross wall of the spacer in a stuffing-box.

Further details of the invention will appear from the following description of several preferred embodiments of the invention with reference to the accompanying drawings in which FIG. 1 is a cross-sectional view of an oil testing engine according to the invention,

FIG. 2 shows a longitudinal cross section on line II II of FIG. 1,

FIG. 3 a partially cross-sectional view of the same engine on line III-III of FIG. 1,

FIG. 4 a partially longitudinal cross section of a variant of the oil testing engine according to the invention, and

FIG. 5 another partially longitudinal view of a special typeof oil testing engine according to the invention.

Mounted on the crankcase '1 of a single-cylinder oiltesting engine as shown in FIG. 1 is the cylinder block 2 with the cylinder liner 3 topped by the cylinder head 4. The crankcase 1 is divided by means of a partition 5 forming part of the crankcase and inclined towards one side of the engine. This partition separates the crank chamber 6 from the chamber 7 around the counterbalancing shafts 8 of the engine. As shown in the drawing, the engine comprises two counterrotating counterbalancing shafts 8 providing mass equilibrium of the first order. If necessary, two additional counterbalancing shafts providing mass equilibrium of the second order might be located in chamber 7.

The partition 5 has an aperture which can. be closed by means of a removable cover 9 and through which chambers 6 and 7 of the crankcase can be interconnected if necessary.

At the front end of the engine, the control wheels 10 for the operation of the camshafts, fuel-injection pump, oil pumps and counterbalancing shafts are located and covered by means of a cover 11 separately mounted on the crankcase 1. The crankshaft 12 rotates in two main bearings, of which one main bearing 13 is located in the crankcase I and the second main bearing 14 in a housing insert 15. The crankshaft 12 of this type of engine is sealed off against the crank chamber 6 by means of a circumferential joint 16 located between the main bearings 13 and 14 respectively and the adjacent crank webs of the crankshaft 12. The annular chamber between the main bearing 13 and the adjacent circumferential joint 16 communicates via oil ducts 17 with the control wheel chamber closed by means of the cover I 1. Likewise, oil ducts 17a lead from the annular chamber between the other main bearing 14 and the adjacent seal 16 to a chamber 20 defined on the side of the flywheel 18 between the housing insert and a front cover 19, and sealed off against the outside by means of a circumferential joint 21 and communicating via an oil bore 22 with the oil chamber 7 below the partition 5.

The control wheel cover 11 has a bore which is coax ial in relation to the crankshaft 12 and in which a stuffing-box 23 is inserted, through which the test oil emerging from a supply pipe 24 flows through bores in the crankshaft 12 to the connecting-rod bearing 25 and from there to the piston 26.

The arrangement of the camshaft 28 of the oil testing engine is shown in greater detail in FIG. 3. The bearings 29 of the camshaft 28 are sealed off by means of sealing rings 30 both against the crank chamber 6 and against the control wheel chamber. Only oil emerging from the cylinder head 4 via a bore 27 serves to lubricate the push rod and cam sides, participates in the oil test and is drained via a discharge bore 30 into the crank chamber 6.

The test oil collected in the crank chamber 6 is drained via the inclined partition 5 into an oil sump 31 laterally adjoining the crankcase 1 and located inside a cover 32 mounted on the side of the crankcase 1. From the oil sump 31 the oil is delivered through a return pipe 33 and an oil filter (not shown) and an oil cooler to the usual oil circulating system. Upon removal of the cover 32 both the cover 9 of the partition 5 and the fixing bolts 34 of the split head of the connecting rod 35 become accesible.

The oil chamber 7 below the partition 5 is closed by A means of an oil pan 36 forming an oil sump 37. The oil from the pan 36 is delivered via a return pipe 38 to a separate second oil-circulating system (not shown in the drawing). The control wheel chamber closed by means of the cover 11 communicates via a preferably lockable bore 39 with the oil chamber 7.

Thus the internal combustion engine for oil testing according to the invention comprises two entirely separate lubricating circles, one of which is fed with the oil to be tested and the other with ordinary commercial lubricating oil. With each of the two lubricating circles a separate oil chamber 6 and 7 respectively, and a separate oil sump 31 and 37 respectively, are associated. In the engine type shown in FIGS. 1 thru 3 the lubricating circle impinged upon by the test oil comprises solely the connecting rod bearing 25, the area of the piston 26, the valves 40 inclusive of the lubrication points of the rocker arms 41, of the push rods 42, of the valve stems 43 and of the camshaft 28. Thus the oil test covers such engine elements as are subject to particularly heavy mechanical and thermal stresses in operation.

The second lubricating circle impinged upon by ordinary lubricating oil includes the main bearings 13 and 14 of the crankshaft 12, from where oil flows through bores 17 and 17a both to the control wheels 10 and to the bearings 44 of the counterbalancing shafts 8. Preferably the lubrication points of the fuel-injection pump 45 and other auxiliary machines, if any, are connected to the second iubricating circle impinged upon by ordinary lubricants.

As a result of the design according to the invention the quantity of oil required for the performance of the oil testis considerably reduced as compared with conventional oil-testing engines, and the time required for, and the expense involved in, the oil test are substantially diminished.

For the purpose of examining the behavior of test oils in the event of increased oxidation the cover 9 of the partition 5 of the crankcase 1 is removed as explained above, so that the oil is allowed to flow from the crank chamber 6 into the oil chamber 7 beneath and is exposed to intensive aeration and oxidation when impinging upon the rotating counterbalancing shafts 8. In that case it is, however, necessary for the counterbalancing shafts 8 to be sealed off against the control wheel cover 11 by means of separate sealing rings 46, while the aperture 39, from which oil from the control wheel chamber normally flows into the oil chamber 7, should be closed. Furthermore, test oil collected in the oil sump 31 is delivered through bores and pipes (not shown in the drawing) to the oil sump 37.

In cases where oil intended for the lubrication of the main bearings is supposed to take part in the oil test, a modified design of the oil-testing engine should be used as shown in FIG. 4. In that case, no circumferential joints 16 are provided and the main bearing 13 is sealed off in the direction of the control wheel cover 11 by means of a sealing ring 47 located in front of the main bearing 13. Test oil flowing ofi the main bearing 13 is drained through a bore 48 and collected in the crank chamber 6. As different from the embodiment of the invention illustrated in FIG. 1, the chamber 20 formed between the housing insert and the cover 19 and sealed ofi against the outside by means of a circumferential joint 21, also communicates with the crank chamber 6 via a bore 49.

According to the invention it is also possible to perform an oil test by examining the test oil only with regard to the lubrication of pistons and piston rings. In that case, a spacer 50 is placed upon the crankcase l with a crosshead shoe 51 extending through it. The bolt 52 of the crosshead shoe 51 is engaged by the forkshaped connecting rod 53 hinged on the crankshaft 12. The spacer 50 carries the cylinder block 2a with the cylinder head 4. The piston 26 is moved by means of a push rod 54 of cylindrical shape and hinged to the same bolt 52 in the crosshead shoe 51. Between the spacer 50 and the cylinder block 2a a stufiing-box-like packing 55 is provided to separate the cylinder chamber 56 from the crank chamber 6.

In that case, the test oil is delivered to the cylinder and piston-ring lubricating system via a spray nozzle 57 and drained via a separate pipe 58. The crankshaft, connecting rod, control wheels and counterbalancing shafts etc. are lubricated by means of the second lubricating circle fed with ordinary commercial lubricant.

With an engine designed as illustrated in FIG. 5, it is furthermore possible to perform yet another oil-testing combination wherein as hereabove described, the lubricant is examined for its purely thermal properties in the closed cylinder chamber 56, while the same lubricant is tested in a separate cycle for purely mechanical stress exerted by the engine elements in the main and connecting-rod bearings using a testing system as shown in FIGS. 1 or 4.

I claim:

1. An internal combustion engine for oil testing, comprising a crankcase, a crankshaft extending through and carried in said crankcase, gear members located in the said crankcase, a cylinder block mounted on the said crankcase, at least one piston slidably guided in said cylinder block, lubricating points of said crankshaft, of said gear members and of said piston provided in the said crankcase and said cylinder block, a lubricating system for the feeding of the said lubricating points, consisting of a first lubricating circle comprising mechanically and thermally highly loaded lubricating points, oil to be tested circulating in the said first lubricating circle, a second lubricating circle arranged in spaced relation to said first lubricating circle and comprising the remaining lubricating points of the engine, normal lubricating oil circulating in said second lubricating circle, an oil-wetted inner space in said crankcase and said cylinder block, a partition arranged in the said oil-wetted inner space and subdividing the same into two separate oil chambers sealed ofi against each other, the first of said oil chambers including the lubricating points of the first lubricating circle supplied with the oil to be tested, the second of said oil chambers including the remaining lubricating points of the second lubricating circle supplied with ordinary lubricating oil.

2. An internal combustion engine for oil testing according to claim 1, further comprising passages for said gear members from said first oil chamber to said second oil chamber, a gasket each located at one of said passages and sealing said two oil chambers off against each other at these passages, said partition being arranged in said crankcase and designed as a crosswall of said crankcase.

3. An internal combustion engine for oil testing according to claim 2, wherein the said partition of the crankcase is inclined in relation to a horizontal plane.

4. An internal combustion engine for oil testing according to claim 2, wherein an aperture is provided in the said partition of the crankcase, a removable cover being insertable in the said aperture of the partition and closing the same tightly.

5. An internal combustion engine for oil testing according to claim 2, comprising two crankshaft bearings connected with the first-mentioned lubricating circle impinged upon by the test oil, a sealing ring being provided around thecrankshaft at the inner extremity of each of the said crankshaft bearings.

6. An internal combustion engine for oil testing according to claim 2, comprising two crankshaft bearings connected with the second lubricating circle impinged upon by ordinary lubricant, a sealing ring each being provided around the crankshaft at the outer extremity of each of the said crankshaft bearings.

7. An internal combustion engine for oil testing according to claim 1, further comprising a spacer inserted between said crankcase and said cylinder block, a crosswall arranged in the said spacer and defining said partition separating said first oil chamber including lubricating points impinged upon by the oil to be tested and pertaining to the cylinder block from said second oil chamber including lubricating points located beneath said spacer and supplied with ordinary lubricating oil, in such a manner as to provide an oiltight seal.

8. An internal combustion engine for oil testing according to claim 7, comprising a crosshead shoe slidably guided in the said spacer, a bearing bolt arranged in transverse relation in the said crosshead shoe, a connecting rod, an upper extremity of which is hinged on the said bearing bolt, a lower extremity of the connecting rod being hinged on the crankshaft of the engine, a push rod hinged to the said bearing bolt and extending through the said crosswall of the spacer, an upper extremity of the said push rod being hinged to the piston of the engine, a stuffing-box inserted in the said crosswall of the spacer and tightly encompassing the said push rod at the point where it extends through the crosswall. 

1. An internal combustion engine for oil testing, comprising a crankcase, a crankshaft extending through and carried in said crankcase, gear members located in the said crankcase, a cylinder block mounted on the said crankcase, at least one piston slidably guided in said cylinder block, lubricating points of said crankshaft, of said gear members and of said piston provided in the said crankcase and said cylinder block, a lubricating system for the feeding of the said lubricating points, consisting of a first lubricating circle comprising mechanically and thermally highly loaded lubricating points, oil to be tested circulating in the said first lubricating circle, a second lubricating circle arranged in spaced relation to said first lubricating circle and comprising the remaining lubricating points of the engine, normal lubricating oil circulating in said second lubricating circle, an oil-wetted inner space in said crankcase and said cylinder block, a partition arranged in the said oil-wetted inner space and subdividing the same into two separate oil chambers sealed off against each other, the first of said oil chambers including the lubricating points of the first lubricating circle supplied with the oil to be tested, the second of said oil chambers including the remaining lubricating points of the second lubricating circle supplied with ordinary lubricating oil.
 2. An internal combustion engine for oil testing according to claim 1, further comprising passages for said gear members from said first oil chamber to said second oil chamber, a gasket each located at one of said passages and sealing said two oil chambers off against each other at these passages, said partition being arranged in said crankcase and designed as a crosswall of said crankcase.
 3. An internal combustion engine for oil testing according to claim 2, wherein the said partition of the crankcase is inclined in relation to a horizontal plane.
 4. An internal combustion engine for oil testing according to claim 2, wherein an aperture is provided in the said partition of the crankcase, a removable cover being insertable in the said aperture of the partition and closing the same tightly.
 5. An internal combustion engine for oil testing according to claim 2, comprising two crankshaft bearings connected with the first-mentioned lubricating circle impinged upon by the test oil, a sealing ring being provided around the crankshaft at the inner extremity of each of the said crankshaft bearings.
 6. An internal combustion engine for oil testing according to claim 2, comprising two crankshaft bearings connected with the second lubricating circle impinged upon by ordinary lubricant, a sealing ring each being provided around the crankshaft at the outer extremity of each of the said crankshaft bearings.
 7. An internal combustion engine for oil testing according to claim 1, further comprising a spacer inserted between said crankcase and said cylinder block, a crosswall arranged in the said spacer and defining said partition separating said first oil chamber including lubricating points impinged upon by the oil to be tested and pertaining to the cylinder block from said second oil chamber including lubricating points located beneath said spacer and supplied with ordinary lubricating oil, in such a manner as to provide an oil-tight seal.
 8. An internal combustion engine for oil testing according to claim 7, comprising a crosshead shoe slidably guided in the said spacer, a bearing bolt arranged in transverse relation in the said crosshead shoe, a connecting rod, an upper extremity of which is hinged on the said bearing bolt, a lower extremity of the connecting rod being hinged on the crankshaft of the engine, a push rod hinged to the said bearing bolt and extending through the said crosswall of the spacer, an upper extremity of the said push rod being hinged to the piston of the engine, a stuffing-box inserted in the said crosswall of the spacer and tightly encompassing the said push rod at the point where it extends through the crosswall. 